Col Sullivan joined the “family business” straight out of high school under the Regular Officer Training Program. After graduation from the University of Manitoba and classification training he was commissioned as a Signals Officer. He held a number of field positions including as Commanding Officer of 2 Mechanized Brigade Group HQ and Signal Squadron and as the CO of 21 Electronic Warfare Regiment. He later held staff positions in project management and gained experience at the operational level during his three years as the J6 with the Canadian Special Operations Forces. He has two operational deployments to Afghanistan. In 2014 he was appointed to the position of the Director Land Command Information/Army G6 in the Canadian Army headquarters.